Whisk together the flour, cocoa powder, confectioners sugar and salt. Set in the fridge to chill for about 10 minutes.
Either using a pastry blender, fork, standing mixer, or your fingers work the butter into the dry ingredients. If using a standing mixer use the paddle attachment on the lowest speed. Mix until the butter is in pea size lumps.
Add the ice cold water 1 tablespoon at a time while mixing, then add just enough water to form the dough.If you squeeze it in your hand it will stick together but not stick to your hand. Transfer the dough to a piece of wax or parchment paper, fold the dough over on itself 3 to 4 times and form into a ¾ inch disk. If you find the dough is sticking to the paper, lightly dust with cocoa powder.
Roll the edge of the disk to smooth it out, wrap with plastic wrap and let it rest in the fridge for 30 minutes.
Preheat the oven to 400°F. Lightly grease a 9-inch pie pan.
After the dough is rested, sprinkle a flat surface with cocoa powder and roll the dough out to roughly 13-inch circle. Transfer it to the prepared pie pan and trim the edges to a 1-inch overhang over the side of the pie pan. Tuck the edges up and under and crimp them using your fingers. Transfer the prepared pie pan to the fridge to chill for 10 minutes.
Line the prepared crust with foil and fill with pie weights or dried beans, moving more beans towards the sides of the pan to keep them from 'slipping' while baking.
Bake the crust for 10 minutes. Move it to a cooling rack and remove the foil with the pie weights/beans. Reduce the oven temperature to 350°F.